Screw driving machine



g- 2 A. R. HAVENER SCREW DRIVING MACHINE 4 Sheets-Sheet 1 Filed April 4. 1947 A. R. HAVENER 2,605,792

SCREW DRIVING MACHINE Aug. 5, 1952 Filed April 4. 1947 '4 Sheets-Sheet 2 7 W? Z 7. A a 7 i l o Ab a W M arw A. R. HAVENER I SCREW DRIVING MACHINE Aug. 5, 1952 4 Sheets-Sheet 3 Filed April 4. 1947 JIEWW r/Mww A. R. HAVENER SCREW DRIVING-MACHINE Aug. 5, 1952 '4 Sheets-Sheet 4 Filed April- 4, 1947.

1222a 02' /ZZZ/XZW W W Patented Aug. 5, 1952 s'cREWf DRIVING MACHINE Arthur R. Havener, Wayland; Mass, assignor t'o- Judson: L. Thomson Manufacturing Company, Waltham Mass. a corporation .of. Massa.chu,-

ApplicationApril' 4, 1947; Serial No. 739,308

drive for the screw driver.

Still another object isto provide amachine wherein the entire driving mechanism ismoved by power under accurate control by the operator.

A further object is to improve the control of' the screws from the initial feed until the screw'is driven so as to provide against failure to drive'or'impr'oper driving'of the screw.

For a complete understanding of thisinvent'ion, reference may be had: to the accompanying drawings in whi'ch Figure'l is a front elevation'of'a' machine embo'dying'the invention.

Figure 2 is a left side elevation of the same.

Figures 3 and 4' are detail sectional views on lines 3-3 and-4 -fl; respectively, of Figure 2.

Figure 5 is a detail sectional view on line 5-5 of F'igurel butshowing a screwat the start of the driving operation and before power drive has commenced.

Figure 6' is a view somewhat similar to Figure 5;-but with certain parts shown in elevation and with the clutches closed and the screw being power driven.

Figure 7' is a view similar to a portion ofFigure 1, but'with parts omitted and certain parts in section and showing a screw in position to 'be driven.

Figure 8 is a View similar to Figure 7, but showing the parts at the end of the driving operation but while thescrew driver isstill in engage'ment' with the driven screw.

Figure 9 is a detail sectional viewon line 9-9 of Figure'B.

Figure 10 is a diagrammatic view of the machine and the raising and lowering mechanism for the screw driver.

of the sides and threadedinto the other.

Threadedon the: screw 3 and" withinthe post 2- is a nut 8 (see-Figure 4-) into -which' extend the inner unthr'ead'ed ends 9 of a'pair of screws I 0 2" threaded through the sides of the bracket 5.

Thus by loosening the screws 1- and turning the handle 4; the heightof the bracket 5 from the forward portion of the support I may be adjuste d as desired, after which by tightening the screws 1 the bracketmay be securely fixedin adjusted position.

The bracket 5', asshown best in Figure 4, has a; cha nnel-shapedportion |2to the side walls I3 ofwhich are secured angle members I4, the inturned flanges l5 of which are spaced from the forward face of the walls 13 to form ways in which a carriage I6 is vertically slidable. This carriage I6 has a forked portion l1 projecting rearwardly between the side walls l3 and between the branches of this fork ispivoted on the cross pin IS, a cross head I9 secured to the lower end of a piston rod 20. This piston rod 20 is slidably mounted through the head 2| of a cylinder 22 and has fixed at its upper end a piston 23' riding within the cylinder. The upper end wall of the cylinder has an extension 24 which is secured to the bracket 5, as by a cross 'pin 25, which extends through the side walls l3. of the bracket 5. By admitting fluid under pressure above or below the piston 23, this piston may be lowered or raised, causing corresponding motion of the carriage l6. Fluid pressure connections to the cylinder 22 above and below thepiston 23 comprise the'pipes 26 and 21 which extend out through one of the walls 13 where they are connected to a suitable source of fluid pressure as will later appear; The carriage lfi'has'a pair of forwardly and outwardly projecting flanges 30 which slidably engage the forward faces of the members I5. I

I To the carriage [6 there is clamped, as by'a clamping strap 3|, a unit comprising a cylindrical motor casing 32 having a tapered lower end 33- to which is threaded a tubular extension 34. This extension 34 may project downwardly through holes in a pair of spaced cross frame members 38 and 39 of the carriage. These cross frame members 38 and 39 and the'strap 3| removably secure the unit comprising the motor casing 32 and the extension 34 to the carriage I6 so as to move therewith.

The tubular extension or sleeve 34, as shown best in Figures 5 and 6, carries a clutch mechanism which connects the motor rotor 40, extending below the motor casing 32, with ascrew driver drive shaft 4|, at the lower. end of the sleeve 34. This shaft 4| has a polygonal socket 42 in its lower end into which may be inserted the correspondingly'shaped shank 23 of the screw driver 44 having the usual bit 45 at its lower end for engagement in the slot 46 of the head of the screw 41 to be driven. This screw driver shank is removably held in the socket 42 by means of a latch ball 48 backed up by a circular spring 49 surrounding the driver shaft M, the ball ridingin a reduced portion 50 of the screw driver. r

The screw driver 44 is slidably and rotatably mounted within a sleeve 52 held to a cap 56 by a sleeve 51 threaded on the lower end of the cap and having an inturned flange 58 engaging beneath a shoulder 59 on the sleeve 52. The cap 56, in turn, is internally threaded as at 60 into the lower end of the extension 34. The driving shaft 4I carries one portion 65 of a toothed clutch, the mating portion 66 of which is journaled in a ball bearing 61 carried by the extension 34. Above the ball bearing 61 the clutch member 66 is provided with an externally threaded shank I on which is threaded a nut TI having peripheral holes I2 therein which can be reached through openings I3 through the extension 34 by a tool, by which the nut Il may be turned to adjust it axially on the shank portion 10. This nut II supports a washer 15 on which is seated a coil spring I6. The upper end of the spring I supports a clutch collar 11 keyed on the shank l0 and'having inclined clutch teeth which may mesh with a mating clutch portion I8 on the lower end of the rotor 40.

The-clutch faces of the parts TI and 78 are yieldingly held in contact by the sprin I6, but when a sufiicient torque is exerted between these parts, the clutch element 'I'I will be forced away from mating relation to the clutch portion I8 against the pressure of the spring 1'6 and rotarily disconnect the rotor 40 from the sleeve IS. The drive shaft 4! is slidable relative to the clutch member 66 and for this purpose, and for centering the two relative to each other, it is provided with a central reduced diameter extension 80 slidable through the portion I0 but normally pressed downwards as by a spring 8| bearing on its upper end. When the carriage with the motor and screw driver are lowered until the lower end of the screw driver contacts the head of the screw, further lowering pressure, which stops the further descent of the screw driver, lowers the clutch element 56 into engagement with the clutch element 55. The motor being rotated and the clutch elements ll and it being in driving contact by reason of the pressure of the spring I5, and therefore rotating, this produces a power rotation of the drive shaft 4! and the screw driver, which thus acts to screw the screw 41 into the work which is supported beneath the screw driver on the support I. As soon as the screwis fully driven and is stopped from further rotation, the resistance to turning thus imposed on the clutch element 'I'I causes this clutch element to be retracted against the pressure of the spring I6, operatively disconnecting the motor rotor 40 from the clutch element ii. The operator then causes the carriage to be lifted to remove the screw driver from the screw, this permitting the clutch element to drop out of contact with the driving clutch element 60, and permitting the spring "It to return the clutch element 'I'l into driven relation to the clutch element I8, the clutch element I? being keyed to the portion I0 so that when it is rotated, the upper clutch element 65 is also rotated.

The up and down motion of the carriage which is controlled by fluid pressure supplied to and discharged from the cylinder 22 is controlled by the operator by means illustrated in Figure 10. The machine is supported on a table or bench and beneath this is a four-way valve controlled by a foot pedal 92. By depressing this foot pedal, fluid pressure from a suitable source (not shown) delivered to the pipe 93, is conducted through the valve 9 I- to thepipe 26, while the pipe 2'! from the lower portion of the cylinder 22 is connected through the valve 9! to the discharge pipe 94. This causes the carriage with the screw driver mechanism to descend to drive the screw. On the completion of the driving operation, the operator removes pressure from the pedal 92, which is allowed to rise, connecting the pipe 26 to discharge and the pipe 21 to pressure supply in the position shown in Figure 10, whereupon the carriage is lifted to its upper position preparatory to another screw driving operation.

Screws are delivered one by one from a suitable supply hopper Iflil through a rotary selector IEiI ofwell known construction and which may be actuated by a ratchet mechanism at I02 having a crank arm I020, connected through a link I82I at I022 to a portion of the carriage I6 so that the reciprocation of the carriage intermittently rotates the selector mechanism and supplies screws to the raceway I03. At I04 is a conventional separator which acts to permit but a single screw to pass through the raceway at a time to the driving mechanism. This separator IE4 is connected through a spring arm I045 to the lower end of a lever I34! fulcrumed at I042 and connected at its upper end through a link I043 with the crank arm {328. This delivery of the individual screws is through mating slots I05 in a pair of jaws I06 (see Figure 9) which are arranged lengthwise of the screw driver 44 and when in their upper positions the slots I55 are opposite to the delivery end of the separator I04 in the position shown in Figures 1 and 2. These jaws I35 have in-turned beveled faces IG'I (Figure 9) which are adapted to engage beneath the head of the screw 41 but which may be separated by pressure from the head of the screw and from the lower end of the screw driver to permit this screw to pass out from between them. These jaws I06 are supported on angle-shaped leaf springs IE8, the lower ends of which are formed with arms I00 extending into slots IIO on the outer faces of the jaws. The upper ends of these leaf springs M8 are secured as by a rivet II I to a supporting block I I2 which is slidably guided for vertical motion on a pin i I3 and on a second pin II4 having a head H5 at its lower end which limits the downward motion of the block. This pin I I4 may be fixed in adjusted vertical position as by a set screw I20 extending through an inwardly projecting boss I2I at the lower end of a plate 522 secured to the bracket I2 as by the screws i223. The block H2 is normally held elevated as by a spring I25 reacting between a pair of pins I25 and 12?, the pin I26 projecting from the block H2 and thepin I2? projecting from the plate I22. This elevated position is shown in Figure 1.

As the carriage I6 descends, a portion I30 thereof, as shown in Figure 9, impinges upon the head of a pin I3I mounted for vertical sliding motion through an extension I32 of the block I I2 and surrounded by a heavy spring I33 which reacts between the head of the pin I3! and the extension I32. Depression of this pin I3I acts to impart downward pressure through the spring I33 against the extension I32 and overcomes the tension of the spring I25, thus lowering the block sition to receive the end of the screw, this nut and the work piece are preferably supported on a work support I30 having a spindle retractible against the tension of a spring I31, as shown in Figure 7. i

As the carriage is so lowered, a cam I40 carried thereby (see Figure '1) moves away'from an arm of a bell crank lever I42 fixed to a switch shaft I43, permitting a Spring I44 acting on a switch arm I45 carried by this shaft to swing inwardly and make a contact with the terminals I45 and I41. This establishes an electric circuit through the flexible cable I48 to the motor which has the casing 33, starting the rotation of this motor and through it rotating the clutch member 68. This serves to drag around frictionally therewith the screw driver, the lower end of which is then free to find the slot in the screw head and fall thereinto by gravity. As the carriage continues to descend after the stopping of the block II2 by impingement on the head I I5, further compressing the spring I33 shown in Figure 9, the screw driver, being held from further descent by its engagement with the screw head, causes the relative lifting of the clutch element 65 until it engages the clutch element 65, whereupon the screw driver is rotated by the motor and the screw is driven tight. As soon as the screw is driven tight, which stops further rotation of the screw and the screw driver, the clutch element 11 yields away from the clutch element I8, disconnecting the power drive of the screw driver, whereupon the operator releases his foot from the treadle 92 and allows the fluid pressure to lift the carriage, retracting the screw driver. Through the action of the bell crank lever I42, the arm I50 of the bell crank lever engaging a projection I 5| on the switch arm,'opens the switch, breaking the contacts at I46 and deenergizing the motor. When the screw driver retracts after the block II2 has been fully retracted by the action of its spring I25, it uncovers the passage I05 and permits the succeeding screw released by the screw separator to pass down between the jaws into alinement with the driver and in position for the succeeding driving operation, in the position shown in Figure 1.

From the foregoing description of an embodiment of this invention, it should be evident to those skilled in the art that various changes and modifications might be made without departing from its spirit or scope.

I claim:

1. In combination, a support, a post upstanding from said support, a bracket carried by said post, said bracket having an upright housing provided with an upright way at its forward face, a carriage mounted for motion along said way and having a portion extending into said housing, a

I fluid pressure mechanism comprising a cylinder and piston enclosed within said housing, said cylinder being pivoted between the sides of said housing, said piston having a rod connected to said carriage portion, a vertical spindle carried by said carriage, a tool carried by said carriage in vertical alinement with said spindle and connected for actuation by said spindle, and operator controlled means for admitting and discharging fluid pressure with respect to said cylinder to lower and raise said carriage and the tool carried thereby.

2. In combination, a support, a post upstanding from said support, a bracket carried by said post, said bracket having an upright housing provided with an upright way at its forward face, a carriage mounted for motion along said way and having a portion extending into said housing, a fluid pressure mechanism comprising a cylinder and piston enclosed within said housing, said cylinder being pivoted between the sides of said housing, said piston having a rod connected to said carriage portion, a rotary motor for driving said spindle also carried by said carriage, and operator controlled means for admitting and discharging fluid pressure with respect to said cylinder to lower and raise said carriage and the parts carried thereby.

ARTHUR R. HAVENER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

